The objective of this project is to develop a fiber-optic laser Doppler velocimeter (LDV) probe for real-time in vivo characterization of mucociliary transport mechanisms. The goal is to establish the feasibility of in vivo measurements by (1) developing a fiber-optic, frequency biased, micro-LDV probe and (2) applying the technique for real-time quantitative analysis of ciliary motions. The frequency-biased LDV will allow direct measurements of effective and recovery strokes of cilia without directional ambiguity. The frequency spectrum of the ciliary beats and metachronal waves, mucociliary transport of particles and the spatial and/or temporal correlation of the ciliary motions will be measured. The current research work being performed at the University of Arkansas GIT and elsewhere on the development of fiber-optic cable-based LDV with miniature optical components indicates that the method has the potential for achieving those goals not attainable by any of the previously reported techniques used for in vivo and in vitro studies of ciliary motions. In the proposed study the sensing probe will be connected to the LDV optics by three 5.0 Mum-dia single mode fiber optic cables coupled with a broncho-fiberscope. The miniaturization of the optical probe, as well as the experimental characterization of ciliar functions, will be performed in several steps including ciliary motion measurements on (1) invertebrates such as a mollusk, (2) freshly-excised lung sample, mounted on a mechanical stage and placed in a temperature and humidity controlled chamber, (3) an isolated profused lung model, and finally (4) an intact anesthetized mongrel dog. Once the feasibility of the method is established, a comprehensive three-year proposal will be developed in cooperation with the Pulmonary Division of the University of Arkansas Medical Sciences Campus to focus research on the effects of therapeutic agents and toxic pollutants on the functions of cilia in the upper and lower respiratory tracts in the intact animal models.